Your Digest for Tuesday, Oct 24, 2023 11:59 PM


#2019GM-OCT

[!INFO] Concordance
Concordance exists when all the QRS complexes in the chest leads are either predominantly positive or predominantly negative. Source
Concordance can be Positive or Negative.

cardiacAxisNumberConventions.png

cardiacAxisDeviation.png

VT Vs. SVT

Source
ABCDE
In VT:

  1. Axis will be north-west (-90 to 180)
  2. Broad complxes
  3. Condordant
  4. D - dissociation (AV)
  5. E - Early part of QRS
    1. Because VT depolarizations are initially conducted through the ventricular muscle (and then reach the conducting system), the initial part of QRS complex will be 'slow' -> i.e slurred.
    2. LITFL-SVTVsVT.png

Spyhilis

#2019GM-OCT/Q27
syphilisStages.png
Source

Treponema pallidum cannot be cultured:

Serology and CSF examination are the mainstays for diagnosis. VDRL (Venereal Disease Research Laboratory) and RPR (rapid plasma reagin) tests are nontreponemal tests used for screening for syphilis.

Tertiary syphilis manifestations

General paralysis of the insane

AKA paretic neurosyphilis, dementia paralytica

Tabes dorsalis

A disease of the posterior columns and the dorsal roots.
Physical examination of late neurosyphilis:

Symptoms:

Treatment

IV penicillin


Porphyrias

#2019SBT-OCT/Q21
They occur due to defects in haem synthesis.

Acute porphyria:
Clinical features: Abdominal pain, neuropsychiatric features, seizures and fever.
Can be precipitated by anaesthetic drugs and luteal phase of the menstual cycle.
Anaesthesia for suspected acute abdomen can be catastrophic.

Chronic porphyrias

Treatment

Nephropathies

Nephrotic syndrome in adult can be caused secondary to systemic diseases.
Or due to primary nephropathies.
FSGS, MCD or Membranous nephropathy.

FSGS can be

Membranous nephropathy


^6ae35e


What teriparatide?

Teriparatide is a recombinant fragment of human parathyroid hormone consisting


BoneStructureBritannica.png
Spongy bone = trabercular bone;
Compact bone = cortical bone.

Definitions

Basically a syndrome of weak bones. (increased fragility).
Low bone mass + 'micro-architectural deterioration' leading to enhanced bone fragility and fracture risk.
Bone density is measured at the hip and the spine.

Pathogenesis and risk factors

Loss of bone mass is due to

Risk factors for fragility fractures are BMD dependent or BMD-independent.
(? only the BMD dependent ones are risk factors for osteoporosis)
riskFactorsOsteoporosis.png
Major causes of low BMD explained:
Oestrogen deficiency

[!INFO] Oestrogen deficiency causes ⬆deposition & ⬆⬆⬆ resorption
Oestrogen AND androgen deficiency cause increased bone turover with increased osteoblastic deposition AND increased osteoblastic resorption but resorption >> deposition and this leads to overall loss of bone density.Source

Oestrogen deff also causes:

Glucocorticoids

Ageing

Diagnosis

[!INFO] The gold standard is DXA
It measures bone density per square aread, NOT per unit volume. Even so, it is very accurate.
Falsely high values can be produces by osteophytes in the elderly.

Management options

The goal of management is to prevent future fractures.
Therefore, whether to treat or not and treatment option used depend on the current fracture risk. This is determined by risk scores such as the FRAX score.

Strongest predictor for future fractures is a history of fragility fracture. (i.e you have one, you're likely to get another)

In USA, for example, 10 year hip fracture risk > 3% or major osteoporotic fracture risk > 20% are indications to start treatment.

Management of fractures

Prevention

Pharmacotherapy

All block resorption except teriparatide.

[!INFO] Phamacologic options and efficacy
osteoPorosisPharmacotherapy.png
Raloxifene and Bazedoxifene prevent only vertebral fractures.

[!TIP] Mnemonic:
terryPlayingIbanezHipFractureRiskMnemonic.png

Bisphophoates

Bind to bone hydroxyapetite and inhibit osteoclasts.

Denosumab

Human antibody against RANKL which causes decreased resorption. Given every 6 months. Prevents fractures at all sites. Few side effects. Can cause osteonecrosis of the jaw. Can cause dysuria.

Strontrium ranelate

rarely used due to cardiovascular and thromboembolic events.

Teriparatide

Synthetic PTH analog -> has a 'paradoxical' effect of decreasing resorption.

When under continuous exposure to PTH (e.g., hyperparathyroidism), bone undergoes resorption more than formation, while intermittent exposure to low-dose PTH (like daily administration of teriparatide) induces bone formation more than resorption. Source

It's a daily sub cut injection ; difficult to take.
Used for resistant osteoporosis and severe vertebral osteoporosis.
Contraindicated for fractures due to skeletal mets and osteosarcoma.

SERMS

[!TIP] SERMS: only for the spine
Rarely used to treat osteoposoris
Being 'selective', they don't act on the uterus.
They do act on bone and decrease resorption.
Site of action is tricky: They reduce fracture risk on at the vertebra but they do reduce resorption at both the hip and spine
Increased thromboembolic risk and flushing.

Calcitriol and calcitonin

Not evidence backed; not used.


Management of HSS

Mainstay of management is HSS is fluid.
Insulin is started only if the there is mild ketonaemia.
If there is acidosis (pH < 7.2 or HCO3 < 15) or high ketonemia, manage as DKA.


Primaquine reduces transmisibility. Main action is to eradicate hyponozoites. Also acts against gametocytes but has no effect against asexual blood stages.
(i.e so it works against hypnozoites and gametocytes)


📑Rheumatoid factor


[!INFO] There is significant overlap between conditions having RF and ANA
RFVsANA2.png